The invention relates to the field of computer programs and systems, and more specifically to a method for navigating in a product structure of a product, wherein said product comprises a set of three-dimensional modeled objects.
Computer-aided techniques are known to include Computer-Aided Design or CAD, which relates to software solutions for authoring product design. Similarly, CAE is an acronym for Computer-Aided Engineering, e.g. it relates to software solutions for simulating the physical behavior of a future product. CAM stands for Computer-Aided Manufacturing and typically includes software solutions for defining manufacturing processes and operations.
A number of systems and programs are offered on the market for the design of objects (or parts) or assemblies of objects, forming a product, such as the one provided by Dassault Systèmes under the trademark CATIA. These CAD systems allow a user to construct and manipulate complex three dimensional (3D) models of objects or assemblies of objects. CAD systems thus provide a representation of modeled objects using edges or lines, in certain cases with faces. Lines or edges may be represented in various manners, e.g. non-uniform rational B-splines (NURBS). These CAD systems manage parts or assemblies of parts as modeled objects, which are mostly specifications of geometry. Specifically, CAD files contain specifications, from which geometry is generated, which in turn allow for a representation to be generated. Geometry and representation may be stored in a single CAD file or multiple ones. CAD systems include graphic tools for representing the modeled objects to the designers; these tools are dedicated to the display of complex objects—the typical size of a file representing an object in a CAD system being in the range of one Megabyte per part, and an assembly may comprise thousands of parts. A CAD system manages models of objects, which are stored in electronic files.
In computer-aided techniques, the graphical user interface (GUI) plays an important role as regards the efficiency of the technique. Most of the operations required for manipulating and/or navigating the objects may be performed by the user (e.g. the designers) on the GUI. Especially, the user may create, modify, and delete the objects forming the product, and also explore the product so as to comprehend how objects are interrelated, e.g. a product structure. The product structure is a hierarchical decomposition of the product wherein relationships of the modeled objects forming the product are arbitrarily settled by the user. Traditionally, the product structure is represented as tree, thus forming a so called “product structure tree”. The operations performed on the objects are carried out through dedicated menus and icons which are located on the sides of the GUI. Recently, CAD systems such as CATIA allow calling and displaying these functions nearby the representation of the product. The designer does not need anymore to move the mouse towards menus and icons. Operations are thus available within reach of the mouse. In addition, the operations behave semantically: for a given operation selected by the designer, the CAD system may suggests to the designer, still nearby the mouse, a set of new operations according to the former selected operation that the designer is likely to select.
Also known are Product Lifecycle Management (PLM) solutions, which refer to a business strategy that helps companies to share product data, apply common processes, and leverage corporate knowledge for the development of products from conception to the end of their life, across the concept of extended enterprise. By including the actors (company departments, business partners, suppliers, Original Equipment Manufacturers (OEM), and customers), PLM may allow this network to operate as a single entity to conceptualize, design, build, and support products and processes.
Some PLM solutions make it for instance possible to design and develop products by creating digital mockups (a 3D graphical model of a product). The digital product may be first defined and simulated using an appropriate application. Then, the lean digital manufacturing processes may be defined and modeled.
The PLM solutions provided by Dassault Systèmes (under the trademarks CATIA, ENOVIA and DELMIA) provides an Engineering Hub, which organizes product engineering knowledge, a Manufacturing Hub, which manages manufacturing engineering knowledge, and an Enterprise Hub which enables enterprise integrations and connections into both the Engineering and Manufacturing Hubs. All together the system delivers an open object model linking products, processes, resources to enable dynamic, knowledge-based product creation and decision support that drives optimized product definition, manufacturing preparation, production and service.
Such PLM solutions comprise a relational database of products. The database comprises a set of textual data and relations between the data. Data typically include technical data related to the products said data being ordered in a hierarchy of data and are indexed to be searchable. The data are representative of the modeled objects, which are often modeled products and processes.
In order to work on a product, a user has to be able to know and identify one or more objects (or parts) of the product. In almost all CAD systems, the products are displayed in one or both of two ways. The first way is a 3D representation of all part of the product; this is the most common view of the product. The second way is based on a specification tree which shows a two-dimensional (2D) representation of the product structure. Most of the time, bidirectional behaviors are implemented to enable the user to visualize correspondences between the product structure and 3D representations, and understand the product structure and physical assembly. For instance, using cross highlight capability, the user can either select a 3D part of the 3D representation of the product or a 2D node of the 2D representation of the product structure, and discover its respective 2D or 3D corresponding node or part which is highlighted. However, the highlighting may be performed only if the selected 2D node is visible on the screen and not outside of the virtual field of view due to previous zooming operations in the 3D view.
For navigating the product structure, the user can use functionalities such as “Reframe on” from 2D product structure tree in order to retrieve the 3D part of the selected node. By using this command, the user is able to center an object in the 3D part, by right-clicking the object, either in the 3D or in the 2D tree, and selecting “Reframe On”. The object is then centered in the 3D and fills the viewer. Another functionality is “Center graph” from 3D representation to center the 2D product structure tree on the node containing the selected geometry. The Center graph functionality locates the object in the 2D product structure tree. The 2D product structure tree is expanded down to the selected object's node and is located at the center of the screen. The object is also selected in the 3D representation of the product.
However, the user needs to iteratively repeat this operation level by level, node by node to obtain a complete understanding of the product. This process is thus laborious and time consuming for the user.
Moreover, 3D products get more complex: for instance, a plane may comprise millions and millions of parts, and while the 3D view of the product is immediate and intuitive, it is often partial as, most of the time, the user works on a limited number of parts of the product. Thus, the corresponding 2D product structure tree gets bigger, denser, and are therefore not immediately apprehensible as they comprise all the parts of the product. The navigation of the 2D product structure tree involves expending and collapsing the tree views, which is cumbersome and not intuitive for the user.
In addition, 3D products involve more users in a collaborative environment, and it is therefore more difficult for a user to understand and reuse an existing product which he/she has not designed himself. Thus, the user needs to navigate the 2D product structure in order to comprehend modifications of the product performed by the other users.
Moreover, no CAD users, such as customers, product architect, etc. are using most of the time “only” 3D, and are not looking at complex specification trees. Thus, they do not need and want to navigate the 2D representation of the product structure.
Furthermore, when a user wants to discover and understand an existing product structure, he/she needs to study a complex specifications tree which may take place on the screen and hinder the simultaneous 3D representation. Thus, the view of the 3D representation is disturbed by the 2D product structure.
Therefore, according to the limitations of the existing solution shortly discussed above, there is a need for improving the exploration and the understanding of the product structure of a product.